ISUZU STYLUS GAS PROBLEM

1991 Isuzu Stylus • 120,000 miles

Getting trouble code 44 -O2S Lean, Fuel Metering {9}
Stylus XS. There are two Oxygen sensors.
When I start the car it runs great until it warms up then it seem rough, after driving 5 to 7 miles it starts to surge. When I try to give gas. Gets worse as I drive. When I park and idle sometimes run ok and at time is rough. I have cleaned EGR Valve, replaced and cleaned gas tank, replaced fuel pump and filter.